The present invention relates to rubber mixtures, a process for their preparation and their use.
U.S. Pat. No. 4,048,206 discloses the synthesis of compounds of the general formula X′—Z′—Si(OR′)3N, where X′ can be halogen or HS—, Z′ can be a bivalent hydrocarbon and R′ can be —CH2—CH2— or —CH(CH3)—CH2—.
Furthermore, the synthesis of NCS—CH2—Si(O—CH2—CH2)3N and NCS—CH2—CH2—CH2—Si(O—CH2—CH2)3N by transesterification of the corresponding methoxysilanes with triethanolamine with liberation of methanol is known from J. Gen. Chem. USSR (EN) 45(6), 1975, 1366 (Voronkov et al.).
EP 0 919 558 discloses silane derivatives of the formula R′″—Si(O—CR′R″—CR′R′)3N where at least one R″ is an alkenyloxyalkyl group. These silane derivatives can be used in silicone compounds.
The use of mercaptoalkyltrialkoxysilanes with silicate fillers in sulphur-crosslinked rubber blends is disclosed, inter alia, in U.S. Pat. No. 4,002,594.
A disadvantage of the known mercaptoalkyltrialkoxysilanes in sulphur-crosslinked rubber mixtures is the undesired premature reaction with the rubber during the mixing process, which complicates the processing owing to increasing viscosities of the mixture.